In general, the corners at bottom of a trunk are mounted with corner wheels for pulling the trunk by pull a telescopic pull rod. However, the installation of the corner wheels has many various variations for meeting the requirement of the users. For example, the corner wheel can rotate freely, telescopically move according to the terrain; be hidden; roll in ladder; be enhanced in stability. However, in these design, the corner wheels are retained in the trunk body fixedly and thus is lack of flexibility. Therefore, as the trunk rolls in an uneven ground, it is often large vibrations occurs. Not only the hand holds the telescopic pull rod feels uncomfortable and even the hand leaves from the pull rod so that the trunk lose of control. Moreover, the objects in the trunk will vibrate and collide with each other. Therefore, the objects unendurable to vibration will be harmed, for example, electronic products and glass products. Furthermore, the stability of the corner wheels will be destroyed and thus, noise is induced. In simply, the conventional corner wheels are poor in shock-proof. Even some corner wheels adapts spring or other elastic elements as a buffering means. However, these designs require more components and are difficult in design. In the other hand, as a trunk is used for a long time, the corner wheel is possible destroyed due to too large friction or too large vibration. But the conventional corner wheel is fixedly secured to the trunk, it is difficult to detach, maintain, and update, the normal use of the trunk will be affect so as to induce a great trouble to the user.
Therefore, there is an eager demand for a novel replaceable shock-proof corner wheel of a trunk which can improve the defects in the prior art. Not only the shock-proof effect is provided to a trunk, but also it can be maintained conveniently.